Automatic level gauge for liquids contained in tanks



AUTOMATIC LEVEL GAUGE FOR LIQUIDS CONTAINED IN TANKS INVENTOR.

Il Il Il l. Il |l n ll :i Ti l: n Il Il ll |I |I ll i Rqzzijpiaczo R. c.DEPALAclo Filed Feb. 19, 1945 Patented Oct. 4, 1949 AUTOMATIC LEVELGAUGE FR LIQUIDS CONTAINED IN TANKS Ral Caldern de Palacio, Mexico City,Mexico Application February 19, 1945, serial No. 578,612

VIn Mexico March 1, 1944 Y 4 Claims. (Cl. '7S-299) This inventionlrelates to an improved device in automatic level gauges for liquidscontained in tanks or vessels, preferably stationary, which arecharacterized by being formed by a system of conduits, tubes orreceptacles interconnected, containing in the system a certain quantityof mercury which varies in its level when the quantity of liquid relatedto it and which is in the tank or vessel increases or diminshes, theheight which the level reaches being varied by the pressure in a tubelocated at the bottom of the tank and connected at the end of a tube ofthe system in which the mercury is contained. This system besides, hasin the end of another of the tubes which form it an extension made up byanother tube of smaller diameter and in which a colored liquid of lessspecific gravity has been lodged, which indicates clearly and in anampliiied form the variation of the mercury contained in the tube oflarger diameter, thus enabling the variations of the level of the liquidcontained in the tank to which the gauge is related to be detected andread with accuracy and greater facility.

Until now, certain level gauges have been employed based in thefluctuation of the correlative level of the mercury contained in a tubeof uniform diameter, by means of the pressure exerted in the tank orvessel, the contents of which are to be measured; the use of thesegauges does not permit to ascertain with accuracy the correct measure ofthe vessel, since the variation of the level of the mercury contained inthe tube of uniform diameter is rather small, in comparison with thecorrelative height of the liquid contained in tank and dependingstrictly on the relation of the density between the liquid contained inthe tank and the mercury, for which reason it was thought to improvethese means by reducing one of the extremes of the indicator tube inwhich the mercury is contained and placing in the other end a liquid ofless specic gravity and of distinguishable color which reachesproportionally higher Variations in its level, since this liquid iscontained partly in the tube of large diameter and partly in the one ofsmaller diameter, therefore amplifying in the latter the movements ofthe mercury caused by the variations of the hydrostatic pressure of theuid contained in the tank when varying of level, thus resulting withthis improvement an advantage with respect to all known until now, sinceit is feasible to determine at iirst sight, by Vmeans of the directindication in the tube of smaller diameter in which the colored liquidis contained and/or, aided by a complementary scale, placed close t thistube, to

2 detect very small variations of level in the contained in the tank.

Another advantage which has been attained by the application of theimproved gauges which are herein described is that which enables toobserve or determine in other or different locations of the receptacles,the levels of the liquids contained therein to which the gauges areapplied, it being, furthermore, feasible to use them for liquids ofdilTerent specific gravities, such as water, oil, gasoline, alcohol,Syrups or the like, whether fluids or viscous or even subject todifferent atmospheric uquid pressures, it being necessary in this caseto protain liquids of different specic gravities, a complementary tubeor deposit has been used, which forms a branch of the system of tubeswhich constitute the gauge; varying the diameter' section or `capacityof this tube which forms the branch. The variation of the mercury levelcontained in the tubes which constitute the system can be controlled aswell as the height which the column of the colored liquid contained inthe tube of smaller diameter must reach, to relate at will said heightto that of the fluid contained in the receptacle. One of the forms whichcan be used to vary the diameter or capacity of the branch tube is usingtelescopic tubes which are adjusted to the interior of the branch tubeand in substitution or combination, nuclei solid rods or suitableelements which are introduced within the branch tube till they get incontact with the mercury level or penetrate it, thus enabling to adjustalso the higher level of the colored liquid column, with respect to itspoint of origin or zero point of the indicating scale when the tank tobe measured is empty or contains no fluid.

The characteristic features of the invention are disclosed in thefollowing description and` the attached drawings illustrating saiddescrip-'f' tion, and using the same reference gures to indicate thesame parts shown on the drawings.

receptacles or deposits interconnected and which form the system thatconstitute the indicator which must be connected to the tanks subject tomeasuring by means of the tubes aforementioned, and this gure also showsthe mercury lodged in said system and which must show, by means of atube of smaller diameter which extends from one of its branches andwhich contains a colored liquid, the height or level of the liquidcontained in the tank to which the gauge is applied.

Figure 2 is a modiiication of the preceding figure in which areconnected the open ends of the system which form the level gauge to acommon tube connected directly to the tank subject to measuring whenthis latter has a diierent pressure to that of the atmosphere,

Figure 3 is an enlarged fragmentary View in section showing a portion ofmy device.

Figure 4 is a modication of the device shown in Figure 1.

Figure 5 is a transverse section taken on the line 5 5 of Figure 4.

The automatic level gauge, as illustrated in the drawings, comprises atube I, of adequate material, preferably i translucid or transparentmaterial, bent in such a form as to constitute various communicationswhich form the system in which a certain quantity of mercury iscontained, stretching at its end 2 into one or several branches, with atube of smaller diameter 3, containing among these a colored liquid ofless specific gravity, which serves to indicate by itself or aided bythe scale 4, the variations of level of the liquid contained in the tank5, which is reached by a tube 6, which can be protected by a thermic orheat insulating covering ta, when the liquid contained in the tank has adifferent or varying temperature with respect t0 that of the atmosphere.

Also the tube 6, can have an amplication on its end 6b, in combinationwith a diaphragm 6c which prevents the access of vapors when the tankcontains volatile uids, it being necessary to employ in this instance asensitive diaphragm that will allow the transmission of the variationsin pressure without being aiected by the pasfV sage of the vapors orgases emanating from the volatile fluids.

The tube 6, reaches to the bottom of tank 5, using for the indication,the hydrostatic pressure of the liquid contained in tank 5, exerted onthe mercury column lodged in the system of tubes shown in I, through theair contained in tube 6, since when the quantity o liquid contained incontainer increases or diminishes, it will force simultaneously themercury column to reach a higher or lower level, as well as the columnof colored liquid contained in the smaller tube 3. v

When tank 5 is subject to a pressure diierent from that of theatmosphere, an optional tube I as seen in Figure 2 has been providedwhich connects the end 8, of the tube 3, as well as the end of tube 9,to the gas space of tank 5, to equalize the pressures and obtain onlythe measure of the exerted pressure of the fluid contained in thereceptacle 5. As explained by the aforesaid, the maximum height whichthe column of the colored liquid must reach in the tube 3 of smallerdiameter, or, in other words, the length of the scale 4, depends on twothings, namely: of the maximum height reached by the liquid contained inthe vessel and of the relation of diameter or transversal section of thelarger tube in which the mercury is contained and part of the coloredliquid and the diameter or transversal section of the smaller tube, inwhich the other portion of the colored liquid is contained, since it isclear that when reaching a certain height, the mercury of the largertube 2, displaces certain volume of the colored liquid which passes tothe smaller tube 3', occupying in the latter a greater height whichdepends on the relation mentioned and which might be called relation ofmultiplication of the apparatus. In order that the apparatus have aconstant scale length for tanks of varying heights and/or, containingliquids of different Specic gravtes, it should be necessary to calculatefor each case a relation of adequate multiplication, this beingextremely complicated and impractical. To overcome this diiculty, thefollowing has been done: to a device as the one already described, andwith a given relation of multiplication, a tube 9 has been added as aderivation communicated with the others which form the system in whichthe mercury is contained and which might be called, for example,regulating vase, since this is really its function. This tube orderivation 9, generally will be of larger diameter than those whichcomplete the system, for, by its use, it may be possible to regulate orrelate to a scale of constant length, the different hydrostaticpressures of tanks of different heights (considering these when they arefull), thus enabling to regulate and balance the colored liquid whichmust always reach the higher end of the common scale of the apparatus.

To have the colored liquid reach the higher end of the scale, it will benecessary that the mercury level contained in tube 2 rises to a givenheight; to equalize the combined pressure of the mercury and the coloredliquid, it is necessary that in the derivation formed by tube 9, thelevel of the mercury be raised to a given height and the level of samelowered in tube I, where the equilibrium is obtained with thehydrostatic pressure exerted by the liquid contained in the tank subjectto measuring. The Volume of the mercury displaced in tube I, isdistributed through tubes 2 and 9, or, in other words, the total of thevolumes of the mercury displaced in these tubes 2 and 9 is equal to thevolume of the mercury displaced in tube l, and the hydrostatic pressureexerted by the liquid contained in tank 5, is equilized with thediilerence of mercury levels between the tubes I and 9 and I and 2, plusthe column of colored liquid.

For different hydrostatic pressures produced by different heights of thetank 5, considering these to be always full, various differences inheights are obtained between the levels of mercury contained in thetubes I and 2; but, as already said, the levels reached by the mercuryin tubes 2 and I, must be xed and determined; therefore, the only levelwhich will descend to diierent heights will be that of the mercurycontained in tube I, provided the condition is followed that the Sum ofthe volumes of mercury displaced in tubes 2 and 9, is equal to thevolume of mercury displaced in tube i, a condition that is easilycomplied with by varying the section or capacity of tube 9, by which itis possible to vary the volume of the mercury displaced in said tube 9,and therefore it will have been possible to have the mercury raise tothe proper heights in tubes 2 and il, with diierent displacements intube I. A form of manner of varying the section or Capacity of tube 9 isby introducing in it a combination or substitution, concentrictelescopic tubes I0, II, and I2 as seen in Figures 4 and 5 and/or, solidrods I3, as seen in Figures 1 and 2 of different diameters with whichthe two conditions of equilibrium can be satisfied; that of thehydrostatic pressure exerted by the liquid contained in tank 5, with thediierences in height of the mercury levels between tubes I and 9, and Iand 2, plus the height of the colored liquid, and that the volume of themercury displaced in tube I be equal to the sum of the Volumes ofmercury displaced in tubes 2 and 9.

When tank 5, which contains the liquid whose weight, volume or densityhas to be gauged, is found at a different pressure other thanatmospheric, conduits or tubes such as I2 will be used, which willconnect to the gas space of the tank subject to gauging with the ends ofeach one of the tubes 3 and 9, and which usually are open to theatmosphere when the liquid contained in the tank is also free to theatmosphere and not subject to a dilerent pressure.

I claim:

1. A tank gauge comprising a horizontally disposed tubular member, apair of upwardly extending tubular columns one at each end of said firstnamed member, mercury in said tubular member and extending partly intosaid columns, a pipe communicating one of said columns with a tank, anindicating column extending coaxially from the other one of said columnsand having a smaller diameter than said other column, an intermediatecolumn between said pair of columns, said mercury also extending partlyinto said intermediate column, and a calibrating member in saidintermediate column and adjustable lengthwise thereof.

2. A tank gauge comprising a horizontally disposed tubular member, apair of upwardly extending tubular columns one at each end of said rstnamed member, mercury in said tubular member and extending partly intosaid columns, a pipe communicating one of said columns with a tank, anindicating column extending coaxially from the other one of said columnsand having a smaller diameter than said other column, an intermediatecolumn between said pair of columns, said mercury also extending partlyinto said intermediate column, a calibrating member in said intermediatecolumn and adjustable lengthwise thereof, a pipe connecting the upperend of said indicating column with said tank, and a pipe connecting saidinterme- 6 diate column with said latter named connecting pipe.

3. A tank guage comprising a horizontal tubular member, a verticallyextending tubular column at each end of said member and communicatingtherewith, a reduced diameter indicating tube formed coaxially with andextending upwardly from one of said columns, a vertically extendingcalibrating column communicating with said member intermediate the endsthereof, mercury in said member and extending partly into said tubularcolumns and said calibrating column, a pipe connecting the other of saidtubular columns with a tank, and calibrating rod means disposable insaid calibrating column and adapted to vary the cross sectional area ofsaid calibrating column.

4. A tank guage comprising a horizontal tubular member, a verticallyextending tubular column at each end of said member and communicatingtherewith, a reduced diameter indicating tube formed coaxially with andextending up; wardly from one of said columns, at least one verticallydisposed tubular calibrating column communicating with said member,mercury in said member and extending partly into said tubular columnsand said calibrating column, a pipe connecting the other of said tubularcolumns with a tank, and calibrating rod means disposable in saidcalibrating column and adapted to vary the cross sectional area of saidcalibrating column.

RAL CALDERN DE PALACIO.

REFERENCES CITED The following references are of record in the I'lle ofthis patent:

'UNITED STATES PATENTS Number Name Date 813,096 House Feb. 20, 19061,257,965 Bailey Mar. 5, 1918 1,361,142 Cook Dec, 7, 1920 1,442,134Dunajeff Jan. 16, 1923 1,499,759 Bacharach July 1, 1924 2,337,171 WintonDec. 21, 1943 FOREIGN PATENTS Number Country Date 839,749 France Jan. 7,1939

